This invention relates to fluid operated torque wrenches. More particularly, this invention relates to low profile or "in line" torque wrenches which are usable in environments where access to fastener elements to be torqued (e.g., a bolt head) and to a ground element for reaction (e.g., an adjacent bolt head) is limited.
Fluid operated torque wrenches of the type under consideration usually have a fluid powered piston rod drivingly connected to an output lever as the operating mechanism of the wrench; and the output lever typically has a ratchet mechanism about an output socket to permit the wrench to be stroked in forward and return directions without removing the wrench from the bolt. The output lever arm travels in a circular arc about the axis of the output socket, and the connection between the piston rod and the output lever has to be able to accommodate relative movement between the piston rod and the output lever to allow for the arcuate movement of the lever arm. As a result, the effective lever arm of the wrench and the angle or direction at which the force is applied from the piston rod to the lever arm changes throughout the stroke of the piston. This impairs the accuracy of the torquing operation of the wrench.